HHH-17255 Add test for issue

hibernate-core/src/test/java/org/hibernate/orm/test/inheritance/MapManyToManyTreatJoinTest.java

@@ -0,0 +1,130 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.orm.test.inheritance;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.Jira;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Inheritance;
+import jakarta.persistence.InheritanceType;
+import jakarta.persistence.JoinTable;
+import jakarta.persistence.ManyToMany;
+import jakarta.persistence.Table;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DomainModel( annotatedClasses = {
+		MapManyToManyTreatJoinTest.JoinedBase.class,
+		MapManyToManyTreatJoinTest.JoinedSub1.class,
+		MapManyToManyTreatJoinTest.JoinedSub2.class
+} )
+@SessionFactory
+@Jira( "https://hibernate.atlassian.net/browse/HHH-17255" )
+public class MapManyToManyTreatJoinTest {
+	@BeforeAll
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			final JoinedSub1 o1 = new JoinedSub1( 1, 123 );
+			final JoinedSub2 o2 = new JoinedSub2( 2, "321" );
+			session.persist( o2 );
+			session.persist( o1 );
+			o1.getSubMap().put( 2, o2 );
+			o2.getSubMap().put( 1, o1 );
+		} );
+	}
+
+	@AfterAll
+	public void tearDown(SessionFactoryScope scope) {
+		scope.inTransaction( session -> session.createQuery( "from JoinedBase", JoinedBase.class )
+				.getResultList()
+				.forEach( session::remove ) );
+	}
+
+	@Test
+	public void testTreatQueryStringProp(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			final String result = session.createSelectionQuery(
+					"select c.stringProp from JoinedBase t join treat(t.subMap as JoinedSub2) c",
+					String.class
+			).getSingleResult();
+			assertThat( result ).isEqualTo( "321" );
+		} );
+	}
+
+	@Test
+	public void testTreatQueryIntProp(SessionFactoryScope scope) {
+		scope.inTransaction( session -> {
+			final Integer result = session.createSelectionQuery(
+					"select c.intProp from JoinedBase t join treat(t.subMap as JoinedSub1) c",
+					Integer.class
+			).getSingleResult();
+			assertThat( result ).isEqualTo( 123 );
+		} );
+	}
+
+	@Entity( name = "JoinedBase" )
+	@Inheritance( strategy = InheritanceType.JOINED )
+	public static abstract class JoinedBase {
+		@Id
+		private Integer id;
+
+		private String name;
+
+		@ManyToMany
+		@JoinTable( name = "sub_map" )
+		private Map<Integer, JoinedBase> subMap = new HashMap<>();
+
+		public JoinedBase() {
+		}
+
+		public JoinedBase(Integer id) {
+			this.id = id;
+		}
+
+		public Map<Integer, JoinedBase> getSubMap() {
+			return subMap;
+		}
+	}
+
+	@Entity( name = "JoinedSub1" )
+	@Table( name = "joined_sub_1" )
+	public static class JoinedSub1 extends JoinedBase {
+		private Integer intProp;
+
+		public JoinedSub1() {
+		}
+
+		public JoinedSub1(Integer id, Integer intProp) {
+			super( id );
+			this.intProp = intProp;
+		}
+	}
+
+	@Entity( name = "JoinedSub2" )
+	@Table( name = "joined_sub_2" )
+	public static class JoinedSub2 extends JoinedBase {
+		private String stringProp;
+
+		public JoinedSub2() {
+		}
+
+		public JoinedSub2(Integer id, String stringProp) {
+			super( id );
+			this.stringProp = stringProp;
+		}
+	}
+}